[SR-Users] NAT'ed RLS setup

Greetings. I have kamailio 3.3.3 setup on server behind the nat. Nat forwards ports for tls/tcp/udp. This setup worked without rls ok. I added necessary modules - rls, pua, xcap etc. Updated a config file and db. Client application uploads xcap documents ok; after app sends subscribe request to list address. Rls/pua modules generate subscriptions to entries in list. But dns resolver finds the public ip as target for subscription. The result is: sip packets cannot reach the server - they are sent to public ip of nat machine. I see it in ngrep output. Nat does not route them back. I add the domain name and _sip._udp.domain with internal ip address to /etc/hosts. But kamailio does not use /etc/hosts when dns caching is active. I do not want to loose dns caching. I made an attempt to run without caching but server was not stable. It crashed couple of times - so i stopped these attempts. Is there way to put eternal domain -> ip bindings into dns cache? I want to put bingings to internal ip - hope it will help. Maybe there is another way to handle this problem?